Blood in the urine (hematuria) can make the urine appear red or brown, depending on the amount of blood, how long it has been in the urine, and how acidic the urine is. An amount of blood too small to turn the urine red may be detected by chemical tests or microscopic examination.

Causes

Blood in the urine may be caused by infection, stones, tumors, injuries, or other problems in the bladder, urethra, ureters, or kidneys. About half of the people who have blood in the urine without pain have a disorder affecting primarily certain specialized blood vessels of the kidney (glomeruli). Sometimes, sickle cell anemia or a related disorder is the cause. Blood in the urine with pain is often the result of a kidney, bladder, or prostate infection or a stone or a blood clot moving through one of the ureters or the urethra.

Evaluation and Treatment

Sometimes, a diagnosis can be made on the basis of the person's symptoms and the results of the doctor's physical examination, urinalysis, and, if infection is suspected, urine culture. Often, however, cystoscopy, imaging studies (such as CT, ultrasound, or MRI), or other tests are needed. If a tumor is suspected, urine is examined for tumor cells. A blood test for sickle cell anemia may be needed for people of African descent who are not known to have the disease.

Treatment is directed at the underlying disorder.

Last full review/revision March 2007 by Ralph E. Cutler, MD